* + mm-page_owner-add-filter-infrastructure.patch added to mm-new branch
@ 2026-04-28 14:17 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-04-28 14:17 UTC (permalink / raw)
To: mm-commits, ziy, vbabka, surenb, mhocko, jackmanb, hannes,
zhen.ni, akpm
The patch titled
Subject: mm/page_owner: add filter infrastructure
has been added to the -mm mm-new branch. Its filename is
mm-page_owner-add-filter-infrastructure.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_owner-add-filter-infrastructure.patch
This patch will later appear in the mm-new branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews. Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.
The mm-new branch of mm.git is not included in linux-next
If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Zhen Ni <zhen.ni@easystack.cn>
Subject: mm/page_owner: add filter infrastructure
Date: Tue, 28 Apr 2026 15:11:09 +0800
Patch series "mm/page_owner: add filter infrastructure for print_mode and
NUMA filtering", v3.
This patch series introduces filtering capabilities to the page_owner
feature to address storage and performance challenges in production
environments.
This patch (of 4):
Add data structure for page_owner filtering functionality and create
debugfs directory for filter controls.
This adds:
- enum page_owner_print_mode with values for full_stack and stack_handle
- struct page_owner_filter with print_mode and nid_mask fields
- Static owner_filter instance initialized with default values
- page_owner_filter debugfs directory
The filter infrastructure will be used to add print_mode and NUMA node
filtering capabilities in subsequent commits.
Link: https://lore.kernel.org/20260428071112.1420380-1-zhen.ni@easystack.cn
Link: https://lore.kernel.org/linux-mm/20260417154638.22370-2-zhen.ni@easystack.cn/
Link: https://lore.kernel.org/20260428071112.1420380-2-zhen.ni@easystack.cn
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
Suggested-by: Zi Yan <ziy@nvidia.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Zhen Ni <zhen.ni@easystack.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/page_owner.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
--- a/mm/page_owner.c~mm-page_owner-add-filter-infrastructure
+++ a/mm/page_owner.c
@@ -54,6 +54,21 @@ struct stack_print_ctx {
u8 flags;
};
+enum page_owner_print_mode {
+ PAGE_OWNER_PRINT_FULL_STACK,
+ PAGE_OWNER_PRINT_STACK_HANDLE,
+};
+
+struct page_owner_filter {
+ enum page_owner_print_mode print_mode;
+ nodemask_t nid_mask;
+};
+
+static struct page_owner_filter owner_filter = {
+ .print_mode = PAGE_OWNER_PRINT_FULL_STACK,
+ .nid_mask = NODE_MASK_NONE,
+};
+
static bool page_owner_enabled __initdata;
DEFINE_STATIC_KEY_FALSE(page_owner_inited);
@@ -973,7 +988,7 @@ DEFINE_SIMPLE_ATTRIBUTE(page_owner_thres
static int __init pageowner_init(void)
{
- struct dentry *dir;
+ struct dentry *dir, *filter_dir;
if (!static_branch_unlikely(&page_owner_inited)) {
pr_info("page_owner is disabled\n");
@@ -981,6 +996,9 @@ static int __init pageowner_init(void)
}
debugfs_create_file("page_owner", 0400, NULL, NULL, &page_owner_fops);
+
+ filter_dir = debugfs_create_dir("page_owner_filter", NULL);
+
dir = debugfs_create_dir("page_owner_stacks", NULL);
debugfs_create_file("show_stacks", 0400, dir,
(void *)(STACK_PRINT_FLAG_STACK |
_
Patches currently in -mm which might be from zhen.ni@easystack.cn are
mm-page_owner-add-filter-infrastructure.patch
mm-page_owner-add-print_mode-filter.patch
mm-page_owner-add-numa-node-filter-with-nodelist-support.patch
mm-page_owner-document-page_owner-filter-features.patch
mm-page_owner-fix-%pgp-format-specifier-argument-type.patch
^ permalink raw reply [flat|nested] 2+ messages in thread* + mm-page_owner-add-filter-infrastructure.patch added to mm-new branch
@ 2026-04-24 11:35 Andrew Morton
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2026-04-24 11:35 UTC (permalink / raw)
To: mm-commits, ziy, vbabka, surenb, mhocko, jackmanb, hannes,
zhen.ni, akpm
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 8708 bytes --]
The patch titled
Subject: mm/page_owner: add filter infrastructure
has been added to the -mm mm-new branch. Its filename is
mm-page_owner-add-filter-infrastructure.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_owner-add-filter-infrastructure.patch
This patch will later appear in the mm-new branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews. Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.
The mm-new branch of mm.git is not included in linux-next
If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Zhen Ni <zhen.ni@easystack.cn>
Subject: mm/page_owner: add filter infrastructure
Date: Sun, 19 Apr 2026 23:55:38 +0800
Patch series "mm/page_owner: add filter infrastructure for print_mode and
NUMA filtering", v2.
This patch series introduces filtering capabilities to the page_owner
feature to address storage and performance challenges in production
environments.
Changes from v1:
- Renamed 'compact' to 'print_mode' with enum type for better clarity
* PAGE_OWNER_PRINT_FULL_STACK (0): print full stack traces
* PAGE_OWNER_PRINT_STACK_HANDLE (1): print only stack handles
- Changed NUMA filter from single node to nodelist with bitmask support
* Uses nodelist_parse() to support "0", "0,2", "0-3", "0,2-4,7" formats
* Uses nodemask_t internally for efficient multi-node filtering
* Output uses %*pbl format (e.g., "0-2", "0,2-4,7")
- Improved memory handling in nid_filter_write using dynamic allocation
* Limit: (100 + 6 * MAX_NUMNODES) to handle worst-case input
These changes address feedback from v1 review:
- "compact" was too vague → use descriptive enum (PAGE_OWNER_PRINT_*)
- Single node filter was limiting → use nodelist_parse() for multi-node support
Problem Statement
=================
In production environments with large memory configurations (e.g.,
250GB+), collecting page_owner information often results in files ranging
from several gigabytes to over 10GB. This creates significant challenges:
1. Storage pressure on production systems
2. Difficulty transferring large files from production environments
3. Post-processing overhead with tools/mm/page_owner_sort.c
The primary contributor to file size is redundant stack trace information.
While the kernel already deduplicates stacks via stackdepot, page_owner
retrieves and stores full stack traces for each page, only to deduplicate
them again during post-processing.
Additionally, in NUMA-aware environments (e.g., DPDK-based cloud
deployments where QEMU processes are bound to specific NUMA nodes), OOM
events are often node-specific rather than system-wide. Currently,
page_owner cannot filter by NUMA node, forcing users to collect and
analyze data for all nodes.
Solution
========
This patch series introduces a flexible filter infrastructure with
two initial filters:
1. **Print Mode Filter**: Outputs only stack handles instead of
full stack traces. The handle-to-stack mapping can be retrieved
from the existing show_stacks_handles interface. This dramatically
reduces output size while preserving all allocation metadata.
2. **NUMA Node Filter**: Allows filtering pages by specific NUMA node(s)
using flexible nodelist format, enabling targeted analysis of memory
issues in NUMA-aware deployments.
Implementation
==============
The series is structured as follows:
- Patch 1: Add filter infrastructure (data structures and
debugfs directory)
- Patch 2: Implement print_mode filter
- Patch 3: Implement NUMA node filter with nodelist support
Usage Example
=============
Enable print_mode and filter for NUMA nodes 0,2-3:
# cd /sys/kernel/debug/page_owner_filter/
# echo 1 > print_mode
# echo "0,2-3" > nid
# cat /sys/kernel/debug/page_owner > page_owner.txt
Sample print_mode output (showing handles only):
Page allocated via order 0, mask 0x0(), pid 0, tgid 0 (swapper),
ts 0 ns PFN 0x40000 type Unmovable Block 512 type Unmovable
Flags 0x3fffe0000000000(node=0|zone=0|lastcpupid=0x1ffff)
handle: 1048577
Page allocated via order 0, mask 0x252000(__GFP_NOWARN|
__GFP_NORETRY|__GFP_COMP|__GFP_THISNODE), pid 0, tgid 0 (swapper),
ts 0 ns PFN 0x40002 type Unmovable Block 512 type Unmovable
Flags 0x23fffe0000000200(workingset|node=0|zone=0|lastcpupid=0x1ffff)
handle: 1048577
Testing
=======
Tested on a system with multiple NUMA nodes. Verified that:
- Filters work independently and in combination
- Print_mode output correlates correctly with show_stacks_handles
- Default behavior (filters disabled) remains unchanged
- NUMA filter works with single node, multiple nodes, and ranges
Example test session:
# cat print_mode
0
# echo "0,1-2" > nid
# cat nid
0-2
# echo "0,2-3" > nid
# cat nid
0,2-3
# echo 1 > print_mode
# head -n 100 /sys/kernel/debug/page_owner
[Shows compact mode output with handles only]
Future Enhancements
==================
The filter infrastructure is designed to be extensible. Potential
future filters could include:
- PID/TGID filtering
- Time range filtering (allocation timestamp windows)
- GFP flag filtering
- Migration type filtering
This patch (of 3):
Add data structure for page_owner filtering functionality and create
debugfs directory for filter controls.
This adds:
- enum page_owner_print_mode with values for full_stack and stack_handle
- struct page_owner_filter with print_mode and nid_mask fields
- Static owner_filter instance initialized with default values
- page_owner_filter debugfs directory
The filter infrastructure will be used to add print_mode and NUMA node
filtering capabilities in subsequent commits.
Link: https://lore.kernel.org/20260419155540.376847-1-zhen.ni@easystack.cn
Link: https://lore.kernel.org/linux-mm/20260417154638.22370-2-zhen.ni@easystack.cn/
Link: https://lore.kernel.org/20260419155540.376847-2-zhen.ni@easystack.cn
Signed-off-by: Zhen Ni <zhen.ni@easystack.cn>
Suggested-by: Zi Yan <ziy@nvidia.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/page_owner.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
--- a/mm/page_owner.c~mm-page_owner-add-filter-infrastructure
+++ a/mm/page_owner.c
@@ -54,6 +54,21 @@ struct stack_print_ctx {
u8 flags;
};
+enum page_owner_print_mode {
+ PAGE_OWNER_PRINT_FULL_STACK,
+ PAGE_OWNER_PRINT_STACK_HANDLE,
+};
+
+struct page_owner_filter {
+ enum page_owner_print_mode print_mode;
+ nodemask_t nid_mask;
+};
+
+static struct page_owner_filter owner_filter = {
+ .print_mode = PAGE_OWNER_PRINT_FULL_STACK,
+ .nid_mask = NODE_MASK_NONE,
+};
+
static bool page_owner_enabled __initdata;
DEFINE_STATIC_KEY_FALSE(page_owner_inited);
@@ -973,7 +988,7 @@ DEFINE_SIMPLE_ATTRIBUTE(page_owner_thres
static int __init pageowner_init(void)
{
- struct dentry *dir;
+ struct dentry *dir, *filter_dir;
if (!static_branch_unlikely(&page_owner_inited)) {
pr_info("page_owner is disabled\n");
@@ -981,6 +996,9 @@ static int __init pageowner_init(void)
}
debugfs_create_file("page_owner", 0400, NULL, NULL, &page_owner_fops);
+
+ filter_dir = debugfs_create_dir("page_owner_filter", NULL);
+
dir = debugfs_create_dir("page_owner_stacks", NULL);
debugfs_create_file("show_stacks", 0400, dir,
(void *)(STACK_PRINT_FLAG_STACK |
_
Patches currently in -mm which might be from zhen.ni@easystack.cn are
mm-page_owner-add-filter-infrastructure.patch
mm-page_owner-add-print_mode-filter.patch
mm-page_owner-add-numa-node-filter-with-nodelist-support.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
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2026-04-24 11:35 Andrew Morton
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